The flange of a simply supported T-Beam is Predominantly in:

Explanation:

A T-beam has a flange and a web. The web (the vertical portion around the middle of the beam that connects the flanges) carries most of the shear load, and the flange (the horizontal piece on top) is responsible primarily for bending stresses.

In a simply supported T-beam subjected to bending under downward loads, a stress distribution develops across the section. This distribution results in compression at the top part of the beam and tension at the bottom. This happens because the top of the beam gets "squeezed" while the bottom fibers get "stretched" under bending.

The flange of a T-beam is generally at the top of the beam section, on the compression side. It's designed to be wider to take significant portions of the compressive stress acting on the beam due to bending moments. Since it is away from the neutral axis, the flange encounters more significant strain and, therefore, higher stress than near the neutral axis.

So, the flange of a simply supported T-Beam is predominantly in compression.